/*
 * Copyright 2002-2015 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      https://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */
package cn.cloud.all.security.config.annotation;

import cn.cloud.all.security.authentication.AuthenticationProvider;
import org.springframework.context.ApplicationContext;
import org.springframework.core.annotation.Order;

/**
 * Lazily initializes the global authentication with a {@link UserDetailsService} if it is
 * not yet configured and there is only a single Bean of that type. Optionally, if a
 * {@link PasswordEncoder} is defined will wire this up too.
 *
 * @author Rob Winch
 * @since 4.1
 */
@Order(InitializeAuthenticationProviderBeanManagerConfigurer.DEFAULT_ORDER)
class InitializeAuthenticationProviderBeanManagerConfigurer extends GlobalAuthenticationConfigurerAdapter {

    static final int DEFAULT_ORDER = InitializeUserDetailsBeanManagerConfigurer.DEFAULT_ORDER - 100;

    private final ApplicationContext context;

    /**
     * @param context the ApplicationContext to look up beans.
     */
    InitializeAuthenticationProviderBeanManagerConfigurer(ApplicationContext context) {
        this.context = context;
    }

    @Override
    public void init(AuthenticationManagerBuilder auth) throws Exception {
        auth.apply(new InitializeUserDetailsManagerConfigurer());
    }

    class InitializeUserDetailsManagerConfigurer
            extends GlobalAuthenticationConfigurerAdapter {
        @Override
        public void configure(AuthenticationManagerBuilder auth) {
            if (auth.isConfigured()) {
                return;
            }
            AuthenticationProvider authenticationProvider = getBeanOrNull(AuthenticationProvider.class);
            if (authenticationProvider == null) {
                return;
            }

            auth.authenticationProvider(authenticationProvider);
        }

        private <T> T getBeanOrNull(Class<T> type) {
            String[] userDetailsBeanNames = InitializeAuthenticationProviderBeanManagerConfigurer.this.context.getBeanNamesForType(type);
            if (userDetailsBeanNames.length != 1) {
                return null;
            }

            return InitializeAuthenticationProviderBeanManagerConfigurer.this.context.getBean(userDetailsBeanNames[0], type);
        }
    }
}
